I wanted to seal my stained desk with varnish for extra protection and durability. But I wasn’t sure if I could apply varnish over the stained wood. So I made some research and here is what I discovered.
You can apply varnish over stain. This is because varnish is a clear top coat used to seal stains and paints after the finish has cured. Varnish is designed with resins and chemicals that make the varnish coating strong enough to protect the stain and material underneath.
Also, the varnish will stick well to stained material without damaging the stain finish. This is because varnish sticks to the stained surface and doesn’t need to penetrate the stain. This reduces the risk of poor paint bonding and damages to the stain finish.
This post reveals more about applying varnish over stain including the steps to carry out the task. So let’s dig in.
How Long After Stain Can I Varnish?
You should wait until the stain cures before applying varnish over it. On average, this will take 6 hours after the stain was applied.
However, there isn’t a general length of time to wait before applying varnish over stain. This is because there are several types and brands of stains. Each with its specific drying and curing time. For instance, water-based stains tend to dry within 2 hours and you can safely apply varnish over the finish in less than 4 hours.
Oil-based stains can take up to 4 hours to dry and over 24 hours to cure enough for varnish application. This is because the solvent in the stain coating has to be fully evaporated before the stain can be varnished. Since water-based stains use water and oil-based stains use oil as the paint solvent, water-based stains can be varnished sooner than oil-based stains. This is because water evaporates faster than oils.
Also, the particles in the stain must have bonded and hardened before the stain can be varnished. This is because the stain will be scuffed and sanded before the varnish is applied. If the stain hasn’t cured, the finish will come off while it’s being prepped for varnish application.
You should know that humidity and room temperature changes can prolong the drying and curing time of stain. For the stain to dry quickly and properly, the stain should be applied at a temperature between 50 and 90 degrees Fahrenheit. The humidity should also be less than 50%.
Also, the additives in the paint coating can shorten or prolong the stain’s curing time. Additives like plasticizers and fungicides take a while to bond with the stain particles so curing can take longer. On the other hand, additives like driers improve the oxidization of the stain it can dry and be varnished sooner.
Related Read: Varnish vs Stain?
How To Apply Varnish Over Stain (Easy Steps)
Applying varnish over stain is a task that will determine the type of finish you end up with. Poor varnish application can result in a cloudy or blurry finish. But not to worry, this guide will reveal all you need to know about applying varnish over stain. First, we are going to need some tools and supplies:
- Dish Soap
- Sponge or Wire brush
- A bowl of water
- Medium-grit sandpaper
- Fine-grit sandpaper
- Spray gun or paintbrush
- Water-based Primer
- Varnish (Satin, medium, or high-gloss)
Here is a quick rundown of how to apply varnish over stain:
- Prepare the work area
- Wash and clean the stain to remove stains and grease
- Remove gloss (Optional)
- Scuff the stain with medium-grit sandpaper
- Apply two coats of water-based primer
- Apply up to 3 coats of varnish (sand between coats)
Now, let’s get to work.
1. Prepare the work area
The first step is to prepare the work area. Bad finishes are often a result of improper preparation.
Remove anything that can cause dust or debris to settle on the varnish while it’s drying. If dust settles on the varnish, you will see and feel dust grain when the varnish dries. It’s generally advised to use painter’s tape on the parts of the surface you don’t want to apply varnish on.
Also, remove furniture and objects around the stained area. It’s advised to spray varnish especially oil-based varnish outdoors to prevent fumes and dust from building inside the home or workshop.
2. Wash and Clean The Stain
Before stain can be varnished, it must have cured and this can take several hours or a few days depending on the type of stain. While this time allows the stain to cure, it also allows dust and grease to settle on the stain especially if the stain was applied in a dusty environment. (This is why you should prep the work area to remove dust).
The dust grain and grease on the stain must be washed off before the stain is varnished if not the finish will come out rough. Also, if the stain has been applied and used before, there might be grease on it.
To wash old stain, mix dish soap with water and use a soapy sponge to gently wipe the stain. This helps to remove greasy stains and dust. Don’t use too much water on the stain especially if it’s a water-based stain. If the stain was recently applied, you don’t need to wash it. A quick wipe with a rag will do. Let the stain dry and then…
3. Remove Gloss (Optional)
If the stain was previously sealed with a top coat, the sealant has to be stripped off too. Oil-based paints and high-gloss latex paints will also need to be stripped lightly to remove the glossy top layer.
4. Scuff The Stain
To allow the varnish to sit on the stain properly, you should abrade or scuff the stain before first. This means you should use sandpaper or sanding sheets to rough up the stain before applying the varnish.
Sanding or scuffing helps to remove imperfections (or paint pimples) in the stain. Sanding also helps to create small ridges that the varnish can bite into. Use medium-grit sandpaper for scuffing the paint. 120-grit or 150-grit will do.
However, if the paint is flaky, swollen, or loose, it’s best to remove the entire coating rather than just sanding. To do this, use a paint stripping compound. If you varnish over loose or flaky paint, the finish will look jaded or worn out.
After scuffing, use fine-grit sandpaper to smoothen the surface of the stain. This helps to achieve a smooth and fine finish.
5. Apply Two Coats of Water-based Primer
Using a paintbrush, apply two coats of the required primer on the stain. You don’t need to sand between coats but you can do a quick wipe on the final coat of the primer with a fine-grit sandpaper. Let each coating dry before laying on another. When the primer has dried fully, you should…
6. Apply 3 Coats of Varnish
Since you have picked your taste of varnish, you can apply the varnish to the stain. It’s generally recommended to spray varnish. This allows you to cover large areas faster. It also helps to achieve even coats easily. You don’t need to thin the varnish before applying it. To spray the varnish, keep the spray gun about 8 inches from the stain. Then ensure to spray overlapping coats.
You can also use a paint roller or a paintbrush for applying the varnish. But since varnish requires detail, you’ll need more than one paintbrush. Angled or chiseled paintbrushes are ideal for applying varnish on furniture and molding since the paintbrush can get in corners.
Allow each coat of varnish to dry before re-coating. This can take a few minutes or hours depending on the type of varnish. You can check the varnish container for help on this.
Tip: Water-based varnish is the best to use over stained wood as the varnish will not yellow over time, unlike oil-based varnish. Let’s go deeper into this.
Which Kind of Varnish is The Best On Stain?
The best type of varnish to use on stain is water-based varnish. This is because the water-based varnish will remain clear for a long time. Oil-based varnish tends to yellow after a few years.
Also, the water-based varnish is easier to apply, clean, and maintain than oil-based varnish. Water-based varnish is also safer to use on stain than oil or chemical-based varnish.
This is because water-based varnish has low levels of VOCs and as such is less likely to pollute the atmosphere or burn the user. Oil-based varnish however has a high volume of chemicals and VOCs. This is one reason oil-based polyurethane varnish produces offensive odor and fumes when applied.
Can I Mix Stain With Varnish?
You can mix stain with varnish but this should be done carefully so you don’t thin the varnish. Varnish being a clear coat doesn’t have paint pigments or colorants in the paint coating. So varnish when dry is clear and not tinted.
To give the varnish color or make it more attractive, you can mix stain with the varnish. But this can’t be done with spray varnish. This is because spray varnish is usually compressed in a spray can and you can only spray it directly on the surface.
You can only mix stain with a varnish that comes in a paint container. This way, you can pour the varnish into a bucket and mix it with a stain. The best stain to mix with varnish is 100% acrylic paint.
Acrylic paint has a high level of paint pigments or colorants and as such will produce a bright color tint if mixed with varnish. Also, acrylic paint is thick. This means you only need little to tint the varnish so there is less possibility of over-thinning the varnish.
Can I Apply Stain Over Varnish?
You can apply stain over varnish but the varnish will have to be well sanded before the stain can be applied over it. This is because varnish is a protective sealant and as such is designed not to let any moisture (oil or water) penetrate it.
Stain however is designed to penetrate a surface to allow it to stick. This is why stains are commonly used on porous wood.
Since the varnish will not let the stain penetrate, the stain can not stick to the varnish. But you can sand or strip the varnish so the stain can penetrate the wood underneath.
Also, it’s advised to use water-based stain over varnish. This is because most varnish finishes are glossy and oil-based stains don’t do well on gloss. Water-based stains however will stick to any type of varnish but paint bonding will be weak if you don’t sand first.
However, it’s not advised to stain over varnish. This is because wood stains are paints designed to alter the color of wood grain and as such will not adhere to varnish properly.
Also, putting stain over varnish is a waste of both paints. Stain is not durable or strong so it will easily wear off or fade if used on varnish. Varnish however is strong and moisture resistant and as such should go over stain and not the other way around.
Related Read: Does Wood Stain Protect Wood?
Here are some other questions commonly asked by DIYers:
What is Wood Stain?
Wood stain is also known as wood dye and the product is used to remove the natural look of wood. If you want to add color to wood or furniture, wood stain is the way to go. It’s usually water-based and has a lot of paint pigments or colorants. So it’s perfect for changing the look of furniture or wooden floor.
Which Varnish is The Best?
In terms of protection and durability, oil-based varnish is the best. In terms of easy cleaning, maintenance, and drying time, water-based varnish is the best.
Which Varnish Should I Use Over Stain?
You can pick either dry or satin varnish, medium-gloss, or high-gloss varnish. These are the 3 categories of varnish finishes.
However, there are several types of varnish under each category. For instance, under dry or satin varnish, you can pick acrylic varnish.
Acrylic varnish has no gloss and the finish is dry, textured, and very colorful. Under high-gloss varnish, you can go for oil-based varnish but be prepared for the high levels of VOCs and odor.
You have a broad range of choices so your choice of varnish will depend on your taste and needs.
Overall, varnish can go over stain and it’s also advised to seal stain with varnish to protect the finish from moisture and damages.
However, you shouldn’t apply stain over varnish except you plan on sealing the stain after. If left unsealed, stain will wear off on varnish. Also, remember to sand and prime before putting varnish over stain.